Orchids

• Orchids are the largest family of flowering plants. And while certain species are found worldwide, from the deserts to the Arctic Circle, the most colorful types, with the boldest flowers, thrive in the tropical regions of Asia, Central America and South America. Among the most popular with indoor greenhouse enthusiasts is the Cattleya orchid, a native of the rain forests of Argentina, Bolivia, Paraguay and Mexico. They like temperatures as high as 90 degrees and extremely humid conditions, which is why they often are grown on humidity trays--metal or plastic trays filled with pebbles and water.
  
  

Ferns

• Ferns also are tropical jungle plants, although like orchids certain species are found in most every climate. But tropical ferns like Maidenhair, Staghorn and Boston like not just low light--whether in jungles or in forests, they grow well below the canopy of trees--but also high humidity. Like orchids, they are best grown on humidity trays, and to prevent browning of the leaves spray them with a mister regularly.
  
  

Gladiolas

• Gladiolas are beautiful tropical plants, known for their long, sword-like leaves and brilliant clusters of big, bold flowers along towering spikes. They are popular "cutting" plants and frequently cultivated for the floral trade. They like lots of water and require full sun or bright light. Gladiolas are native to tropical and even some Mediterranean climates, although most species were discovered in South Africa.
  
  

Begonias

• These lush tropical plants have bright, colorful flowers with textured leaves, from waxy to hairy. Their native habitat spans hot, moist regions in Central and South America, southern Asia and Africa. Begonias can be stemmed, rhizomatous or tuberous, with the latter variety having the biggest, boldest flowers. Begonias won't tolerate full sun but thrive in shady areas, where they can be grown year-round (except for the tuberous variety).
  
  

Calathea

• The calathea family consists of beautiful, colorful plants with dark green ovate leaves and flowers shaped like beehives, rattlesnake tails or snow cones. They spread through rhizomes and are native to the tropical regions of South and Central America. Calatheas thrive in heat and humidity but don't do well in hot, direct sunlight, making them good candidates for indoor greenhouses even in areas where some tropicals can survive outdoors, like coastal Southern California or Florida.